X-RAY-ABSORPTION SPECTROSCOPY AT THE FE L(2,3) THRESHOLD IN IRON-OXIDES

The influence of local order around the iron site on Fe 2p x-ray-absor ption spectra is studied for alpha Fe2O3, FeO, Fe3O4, and gamma-Fe2O3. The experimental spectra are accounted for thanks to a configuration- interaction calculation of Fe L(2,3) x-ray-absorption edge shapes, exp licitly taking into account the exact first-neighbor surrounding of th e cation acting through crystal-field splitting and hopping terms. The peak's splittings and intensities are well reproduced: the contributi ons of the various iron site symmetries and valencies are discriminate d. The nature of insulating gap for each compound is deduced.